Your job as a New Zealander is to save lives - and to do that you have to stay home, says Prime Minister Jacinda Ardern.

"New Zealand, be calm, be kind, stay at home.

"We can break the chain."

The nation will go into an extreme lockdown at 11.59pm this evening as we move to alert level 4 to try slow the spread of the deadly Covid-19 coronavirus.

A state of nationwide emergency was officially declared at 12.21pm today for the second time in this country's history.

This gives Civil Defence director Sarah Stuart-Black extraordinary powers to enforce the nationwide lockdown - including road blocks if necessary - stopping people from doing certain activities, and powers of requisition.

There are 50 new confirmed and probable coronavirus cases in the last 24 hours, bringing the total to 205.

Community transmission attached to cases in Marist College and from the World Hereford Cattle conference in Queenstown, while there are four other cases of community transmission.

Ardern's full speech to Parliament:

Mr Speaker,

• 40 new cases of coronavirus: Total now at 155
• Non-essential businesses face fines, immediate shutdowns

I wish to make a Ministerial Statement under Standing Order 347 in relation to the recent declaration of a State of National Emergency.

Having considered the advice of the Director Civil Defence Emergency Management, the Minister of Civil Defence declared a State of National Emergency for the whole of New Zealand under section 66 of the Civil Defence Emergency Management Act 2002 on March the 25th 2020 at 12.21pm.

This is to manage the spread of the COVID-19 epidemic within New Zealand.

The Minister of Civil Defence took this step because of the unprecedented nature of this global pandemic, and because he considered the response required to combat COVID-19 is of such a degree that it will be beyond the capacity of local Civil Defence Emergency Management Groups to respond to on their own.

This pandemic also requires a significant and coordinated response by and across central and local government.

Also, under section 5 of the Epidemic Preparedness Act 2006, yesterday I issued an Epidemic Notice, nationwide, to help ensure the continuity of essential Government business due to the unprecedented effects of the global pandemic, COVID-19, which is likely to significantly disrupt essential governmental and business activity in New Zealand.

This Epidemic Notice came into effect today, the 25th of March 2020, just after midnight and it will remain for three months with ongoing review, and from which, now further Epidemic Management Notices and Epidemic Modification Orders can be given – particularly across local government, immigration and social services – crucial services that now need flexibility to operate due to the effects of an epidemic in our country and an impending lockdown to prevent the spread of COVID-19.

At 11.59pm tonight, we move to the highest Alert Level of 4, and we, as a nation, go into self-isolation.

The trigger: early evidence of community transmission of COVID-19 in New Zealand.

But unlike so many other gravely inundated countries, we have a window of opportunity to stay home, break the chain of transmission, and save lives. It's that simple.

In this fight against a virus, we have some things on our side.

We are moving into this next phase of our response early. Ahead of any potential over-run of our hospitals, and ahead of any deaths on New Zealand soil. But that doesn't mean we should be complacent. And that's why we must take this period of self-isolation deadly seriously.

This means we will go about life very differently to help slow down the spread of COVID-19.

We all have a role to play.

Only those in essential services will leave home to go to work. All others stay home and stop interactions with those outside the home.

Non-essential business premises close.

Events and gatherings are cancelled.

Schools close.

Public transport is reserved for those undertaking essential services and transport of freight.

Domestic air travel is very limited.

New Zealanders entering at our borders undergo strict measures to isolate or quarantine.

From midnight tonight, we bunker down for four weeks to try and stop the virus in its tracks, to break the chain.

Make no mistake this will get worse before it gets better. We will have a lag and cases will increase for the next week or so. Then we'll begin to know how successful we have been.

I am fully aware that we have moved with huge speed. No other country in the world has moved to these measures with no deaths and so few infections. We have 5 people in our hospitals, none in ICUs or needing ventilators at this stage.

But we have no time to waste. We could have waited to plan ever intricate detail required to execute this closure, till we could answer every single question or circumstance. But, every hour we wait, is one more person, two more people, three more people, exposed to Covid-19.

That is why we did not wait. We established an alert system with clear guidance on when we must act, and why. We asked people to prepare, and then moved decisively.

These moves will be enforced. And we will be the enforcer.

Yesterday I issued the Epidemic Notice and today the Minister of Civil Defence declared a State of National Emergency, both of which provide us the powers for Government to move the country to Alert Level 4.

This is the second time in New Zealand's history that a State of National Emergency has been declared.

The first was on February the 23rd 2011.

It followed the 6.3 magnitude earthquake in Christchurch. It followed the death of many New Zealanders, the total destruction of much infrastructure and the crippling of essential services.

It was declared to allow the greatest possible coordination of local, national, and international resources to work on rescue and recovery. As the other side of the House would recall well.

Today we put in place our country's second State of National Emergency as we fight a global pandemic, as we fight to save New Zealanders' lives. To prevent the very worst that we've seen in other countries around the world from happening here. To protect our essential health services. To cushion the economic impacts of COVID-19.

A State of National Emergency to preserve our way of life.

Every person still at work, interacting with others, increases the risk of the virus spreading exponentially and means we will be in lockdown for longer.

That means people will be out of work longer, doing further damage to livelihood and lives.

There will be no tolerance for that. We will not hesitate to use our enforcement powers if needed.

Through the early and hard measures we've taken at the border, using the powers under the Health Act, the signing of epidemic notices, now, being in a State of National Emergency, we have all of the legislative means possible, all the enforcement powers, all the tools we need, at our disposal to combat the spread of COVID-19.

Under the Civil Defence Emergency Management Act 2002, today's declaration of a State of National Emergency will allow the Director Civil Defence Emergency Management to direct, coordinate and use the resources made available to manage the response to COVID-19.

The Director of Civil Defence Emergency Management may also control the exercise and performance of functions, duties, and powers of Civil Defence Emergency Management Groups and Group Controllers across the country.

While in force, it will allow Civil Defence Emergency Management Controllers to provide for the:

- conservation and supply of food, fuel and other essential supplies

- to regulate land, water and air traffic

- to close roads and public places

- to evacuate any premises, including any public place,

- And if necessary to exclude people or vehicles from any premises or place.

This declaration helps us limit our exposure, and the exposure of the most vulnerable members of our community, to COVID-19. In short, it will help save lives.

An Epidemic Notice further strengthens our response to COVID-19 and helps us manage effectively shutting down the country for the first time.

It does a number of things including allowing for special powers of medical officers of health – and immediately unlocks powers under the Corrections, Health and Electoral Acts.

But importantly an Epidemic Notice sits as an umbrella over further notices that can now be issued, and which have now been issued, to change and modify specific parts of legislation in a common-sense and pragmatic way to keep our systems working in a time of lockdown – and get rid of particular requirements that are impractical to comply with in a time of an epidemic and when in lockdown.

Specifically for our immigration sector:

- Temporary visas are automatically extended to late September.

- This comes into effect from Thursday the 2nd of April 2020 and means travellers with a temporary work, student, visitor, interim and limited, visa expiring before 1 April 2020 who are unable to leave New Zealand must apply online for a new visa. An interim visa will be issued.

- Travellers with a temporary visa due to expire between 1 April and 9 July 2020 will have their visas extended to late September. Confirmation of extensions will be emailed directly to all visa holders.

- Detailed information is on the Immigration NZ website and covid19.govt.nz website but anyone in New Zealand and concerned about their visa should get in touch with Immigration New Zealand.

For our social service sector, an epidemic notice means:

- The Ministry for Social Development can grant emergency benefits to people who would otherwise not be entitled to them (including temporary workers who lose a job) – this sits as a necessary partner to the Government's multi-billion dollar economic assistance package that aims to keep people in jobs and with an income – including wage subsidies for all workers working legally in New Zealand and a deployment package.

- It also allows for extra flexibility in relation to the payment, reinstatement, grant, increase, cancellation, suspension, or variation of benefits

These notices and the powers which they carry are not issued lightly.

The restrictions in place on New Zealanders' movements are the most significant in our modern history. I do not underestimate the gravity of what is being asked of you. But we have a limited window of opportunity and we must use every weapon we have.

New Zealanders want to see that these measures are being complied with but in a way that we're used to seeing as New Zealanders.

As Police Commissioner Mike Bush said, the Police and the Military will be working together and there is assistance at the ready as required. If people do not follow the message here today, then the police will remind people of their obligations. They have the ability to escalate if required. They can arrest if needed, they can detain if needed.

But these are tools of last resort, in a time when I know New Zealanders will rally. Because that is what we do.

And so, as we enter into a stage that none of us have experienced before, I want to share a few final messages.

Firstly, you are not alone. You will hear us, and see us, daily as we guide New Zealand through this period. It won't always be perfect. But the principle of what we are trying to do is the right one.

Secondly, success won't be instant. The benefit of what we do today, won't be felt for many days to come. Expect our numbers to keep rising, because they will. But over time, we will see change if we all stick to the rules.

Thirdly, you may not be at work, but that doesn't mean you don't have a job. Your job is to save lives, and you can do that by staying home, and breaking the chain.

And finally, if you have any questions about what you can or can't do, apply a simple principle. Act like you have COVID-19. Every move you then make is a risk to someone else. That is how we must all collectively think.

That's why the joy of physically visiting other family, children, grandchildren, friends, neighbours is on hold. Because we're all now putting each other first. And that is what we as a nation do so well.

So New Zealand, be calm, be kind, stay at home. We can break the chain.